Changes In Environmental Temperature Research Articles

Cooperative Control of Bioelectrocatalytic Activity for Thermo- and Photo-Switchable Cup-Stacked Carbon Nanofiber Electrodes Modified with Phase Transition Polymer and Heme Peptide.

Empowering biocatalyst-modified electrodes with the ability to both enforce and perceive will enable the development of intrinsically switchable bioelectrode systems, which exhibit autonomous and heteronomous actions specific to living organisms. However, the electrocatalytic activity of switchable bioelectrodes reported so far has been controlled by changes in the rate of substrate transport to biocatalysts. Here, we prepared a cup-stacked carbon nanofiber (CSCNF) electrode modified with a thermoresponsive N-isopropylacrylamide-based polymer containing peroxidase model compounds (HP). As CSCNFs worked as a converter from near-infrared (NIR) light to heat, bioelectrocatalytic activity of the electrode to H2O2 reduction was reversibly controlled by changes in the amount of electroactive HP, based on expanded and contracted states of the polymers induced by not only environmental temperature changes but also external NIR light irradiation. This intrinsically switchable bioelectrode technique would hold promise for adding new performances in electrochemical biosensors and biofuel cells, for example, autonomous and heteronomous tunable sensitivity and capacity.

Magnetic Torque-Driven All-Terrain Microrobots.

All-terrain microrobots possess significant potential in modern medical applications due to their superior maneuverability in complex terrains and confined spaces. However, conventional microrobots often struggle with adaptability and operational difficulties in variable environments. This study introduces a magnetic torque-driven all-terrain multiped microrobot (MTMR) to address these challenges. By coupling the structure's multiple symmetries with different uniform magnetic fields, such as rotating and oscillating fields, the MTMR demonstrates various locomotion modes, including rolling, tumbling, walking, jumping, and their combinations. Experimental results indicate that the robot can navigate diverse terrains, including flat surfaces, steep slopes (up to 75°), and gaps over twice its body height. Additionally, the MTMR performs well in confined spaces, capable of passing through slits (0.1 body length) and low tunnels (0.25 body length). The robot shows potential for clinical applications like minimally invasive hemostasis in internal bleeding and thrombus removal from blood vessels through accurate cargo manipulation capability. Moreover, the MTMR can carry temperature sensors to monitor environmental temperature changes in real time while simultaneously manipulating objects, displaying its potential for in-situ sensing and parallel task implementation. This all-terrain microrobot technology demonstrates notable adaptability and versatility, providing a solid foundation for practical applications in interventional medicine.

Individual methanogenic granules are whole-ecosystem replicates with reproducible responses to environmental cues

BackgroundIn this study, individual methanogenic (anaerobic), granular biofilms were used as true community replicates to assess whole-microbial-community responses to environmental cues. The aggregates were sourced from a lab-scale, engineered, biological wastewater treatment system, were size-separated, and the largest granules were individually subjected to controlled environmental cues in micro-batch reactors (μBRs).ResultsIndividual granules were identical with respect to the structure of the active community based on cDNA analysis. Additionally, it was observed that the active microbial community of individual granules, at the depth of 16S rRNA gene sequencing, produced reproducible responses to environmental changes in pH, temperature, substrate, and trace-metal supplementation. We identified resilient and susceptible taxa associated with each environmental condition tested, as well as selected specialists, whose niche preferences span the entire trophic chain required for the complete anaerobic degradation of organic matter.ConclusionsWe found that single anaerobic granules can be considered highly-replicated whole-ecosystems with potential usefulness for the field of microbial ecology. Additionally, they act as the smallest whole-community unit within the meta-community of an engineered bioreactor. When subjected to various environmental cues, anaerobic granules responded reproducibly allowing for rare or unique opportunities for high-throughput studies testing whole-community responses to a wide range of environmental conditions.

Temperature change regulates pollen fertility of a PTGMS rice line PA64S by modulating the ROS homeostasis and PCD within the tapetum.

Photoperiod and temperature-sensitive male sterility rice is an important line for two-line hybrid rice, and the changes in the cultivation temperature strictly control its pollen fertility. However, the mechanism by which temperature variation regulates pollen fertility is still unclear. This study obtained stable fertile PA64S(F) and sterile PA64S(S) rice from PA64S by controlling temperature changes. PA64S(F) shows a normal anther development and fertile pollen under low temperature (21°C), and PA64S(S) shows delayed degradation of the tapetum cells, leading to abnormal pollen wall formation and ubisch development under normal temperature (28°C). The accumulation of reactive oxygen species (ROS) positively correlates with the programmed cell death (PCD) process of tapetum cells. The delayed accumulation of ROS in the PA64S(S) tapetum at early stages leads to a delayed initiation of the PCD process. Importantly, we localized ascorbic acid (ASA) accumulation in the tapetum cells and determined that ASA is a major antioxidant for ROS homeostasis. ROS-inhibited accumulation plants (PA64S-ASA) demonstrated pollen sterility, higher ASA and lower ROS accumulation in the tapetum, and the absence of PCD processes in the tapetum cell. Abnormal changes in the tapetum of PA64S(S) rice disrupted metabolic pathways such as lipid metabolism, cutin and wax synthesis, sugar accumulation, and phenylpropane, affecting pollen wall formation and substance accumulation, suggesting that the timely accumulation of ROS is critical for male fertility. This study highlights the central role of ROS homeostasis in fertility alteration and also provides an avenue to address the effect of environmental temperature changes on pollen fertility in rice.

Zero-power infrared switch with two-phase microfluidic flow and a 2D material thermal isolation layer

Wireless sensor nodes (WSNs) play an important role in many fields, including environmental monitoring. However, unattended WSNs face challenges in consuming power continuously even in the absence of useful information, which makes energy supply the bottleneck of WSNs. Here, we realized zero-power infrared switches, which consist of a metasurface and two-phase microfluidic flow. The metasurface can recognize the infrared signal from the target and convert it into heat, which triggers the two-phase microfluidic flow switch. As the target is not present, the switch is turned off. The graphene/MoS2/graphene 2D material heterostructure (thickness <2 nm) demonstrates an exceptionally high thermal resistance of 4.2 K/W due to strong phonon scattering and reduces the heat flow from the metasurface to the supporting substrate, significantly increasing the device sensitivity (the displacement of the two-phase microfluidic flow increases from ~1500 to ~3000 µm). The infrared switch with a pair of symmetric two-phase microfluidic flows can avoid spurious triggering resulting from environmental temperature changes. We realized WSNs with near-zero standby power consumption by integrating the infrared switch, sensors, and wireless communication module. When the target infrared signal appears, the WSNs are woken and show superb visual/auditory sensing performance. This work provides a novel approach for greatly lengthening the lifespan of unattended WSNs.

Low-loss and low-temperature sintering of SrNb2V2O11 with a large positive τf value as an effective temperature compensator

Novel SrNb2V2O11 microwave dielectric was synthesized and proposed as a temperature compensator for Low-temperature cofired ceramics (LTCC)/Ultra-low-temperature cofired ceramics (ULTCC) applications. The X-ray diffractometer (XRD) patterns matched well with the SrNb2V2O11 phase, exhibiting a monoclinic structure and Cc space group over the entire experiment. The presence of the Nb-rich second phase at 850 °C was attributed to the melting of the samples. The microwave dielectric properties were highly correlated with the chemical bond parameters, which were intensively investigated using the P-V-L theory. The specimen sintered at 820 °C reveals dielectric properties, combining an εr of 74.5, Q × f of 13,000 GHz, and τf of 517 ppm/°C. The large positive τf can make the ceramic an effective temperature compensator for LTCC applications. Moreover, the medium-high εr value can also act as a practical material for dielectric resonators used in the base stations, where a stable environment and limited temperature changes are crucial.

Transcriptome Analysis Reveals the Variations in Enzyme Production of Saccharopolyspora rosea A22 under Different Temperatures.

Saccharopolyspora is a key microorganism in the fermentation of traditional fermented foods, capable of producing saccharifying and liquefying enzymes at elevated temperatures. However, the specific mechanisms and regulatory pathways governing Saccharopolyspora's response to ambient temperatures are not yet fully understood. In this study, the morphological differences in Saccharopolyspora rosea screened from traditional handmade wheat Qu at different temperatures were initially explored. At 37 °C, the mycelium exhibited abundant growth and radiated in a network-like pattern. As the temperature increased, the mycelium aggregated into clusters. At 50 °C, it formed highly aggregated ellipsoidal structures, with the mycelium distributed on the spherical surface. Subsequently, we assessed the biomass, saccharifying enzyme activity and liquefying enzyme activity of Saccharopolyspora rosea cultured at 37 °C, 42 °C and 50 °C. Furthermore, transcriptome analysis demonstrated that Saccharopolyspora rosea employs mechanisms related to the carbon metabolism, the TCA cycle, glycine, serine and threonine metabolisms, and microbial metabolism in diverse environments to coordinate its responses to changes in environmental temperature, as verified by the expression of typical genes. This study enhances our understanding of the differences in high-temperature enzyme production by Saccharopolyspora, and offers valuable guidance for the traditional fermented food industry to drive innovation.

Anaerobic digestion of poultry manure to power a poultry farm in Ba: Pilot and techno-economic study

Although poultry is the largest meat by volume produced in Fiji, there has not been any established study, nor application of the anaerobic digestion (AD) of poultry manure (PM) in the country. This paper aims to determine the techno-economic feasibility of the AD of PM to power a poultry farm in Fiji. A pilot scale study was first conducted with mono-digestion batches of poultry manure, and co-digestions with kitchen waste (KW) and newspaper waste (NPW). Solid state anaerobic digestion (SSAD) was employed in all the batches, and the key operational parameters of AD were studied, along with its influence on biogas production. The pilot study revealed that even slight changes in environmental temperature had the greatest effect on biogas production. The most resilient to the temperature changes were the co-digested feedstocks of KW. Yet, given a substantial AD period, the anaerobes in the mono-digesters were able to eventually acclimatize to the SSAD environment, and produce the overall highest biogas production. The pilot study results were then used to conduct a feasibility study of the full-scale design. The analysis showed that the SSAD system would generate 189.46 MWh of electricity annually, with a levelized cost of energy of FJ$0.17/KWh.

A four core fiber temperature and strain dual parameter sensor based on T-shaped taper

A four core fiber temperature and strain dual parameter sensor based on T-shaped taper is proposed and prepared. The sensor is composed of single-mode fiber (SMF), multi-mode fiber (MMF), and four core fiber (FCF). Among them, MMF plays a role in beam expansion, and FCF is tapered and fused with SMF to form a T-shaped taper structure, thereby preparing a sensor based on Mach Zehnder interference principle. When the external environmental temperature and strain change, due to thermal effect and elastic optical effect, the refractive index of the FCF cladding and fiber core changes differently, resulting in shift in the interference spectrum. Based on the temperature and strain sensitivity at different interference valleys, the temperature and strain dual parameter matrix equation of the sensor can be obtained. The experimental results indicate that when the temperature rises within the range of 30 ℃ to 90 ℃, the sensor spectrum shows a red shift phenomenon, and the maximum temperature sensitivity can reach 55 pm/ ℃. When the strain increases within the range of 0 με∼ 2000 με, the transmission spectrum of the sensor exhibits a blue shift phenomenon, and the maximum strain sensitivity can reach −2.6 pm/ με. Finally, based on the experimental results, the matrix equation for dual parameter sensing can be obtained. This sensor is easy to manufacture and has high sensitivity. It can measure sensing parameters normally in micro magnetic and micro electric field environments.

Asymmetrical surface-modified polyester/cotton fabrics for temperature-adaptive moisture and thermal management of human body

Personal moisture and thermal management fabrics that can regulate skin temperature are highly desired for improving human comfort and performance. Here, a symmetric surface modified polyester/cotton fabric (Janus T/C fabric) exhibiting exceptional temperature-adaptive personal moisture and thermal managements was developed. This was achieved by integrating two distinct temperature-sensitive hydrophobic/hydrophilic transition materials through single-sided spray coating technique and in-situ ultraviolet-induced free radical polymerization in 60/40 polyester/cotton blend fabric (T/C fabric, composed of 60 % cotton and 40 % polyester fibers). 2-(2-methoxyethoxy) ethoxyethyl-methacrylate (MEO2MA) was utilized to create lower critical solution temperature (LCST) polymer, while N, N-dimethyl (methacryloylethyl) ammonium propane sulfonate (DMAPS) formed an upper critical solution temperature (UCST) polymer on T/C fabric surface. Fabric’s surface demonstrated a reversible transition in hydrophobicity/hydrophilicity in response to environmental temperature changes. The distinct hydrophobic and hydrophilic surfaces configuration resulted in a remarkable wettability gradient, significantly increased moisture permeability to 6792.5 g/m2·24 h—an increase of 1132.1 g/m2·24 h compared to the 60/40 T/C fabric at 40 °C. Moreover, the Janus T/C fabric provided practical temperature adaptation benefits, offering a cooling effect of approximately 1.2 °C in hot environments and a warming effect of approximately 1.0 °C in cold conditions. These thermal responsive properties make the asymmetric surface-modified polyester/cotton fabric an ideal choice for personalized moisture and thermal management, ensuring optimal comfort across varying temperatures.

Energy-Efficient Smart Window Based on a Thermochromic Hydrogel with Adjustable Critical Response Temperature and High Solar Modulation Ability.

Thermochromic smart windows realize an intelligent response to changes in environmental temperature through reversible physical phase transitions. They complete a real-time adjustment of solar transmittance, create a livable indoor temperature for humans, and reduce the energy consumption of buildings. Nevertheless, conventional materials that are used to prepare thermochromic smart windows face challenges, including fixed transition temperatures, limited solar modulation capabilities, and inadequate mechanical properties. In this study, a novel thermochromic hydrogel was synthesized from 2-hydroxy-3-butoxypropyl hydroxyethyl celluloses (HBPEC) and poly(N-isopropylacrylamide) (PNIPAM) by using a simple one-step low-temperature polymerization method. The HBPEC/PNIPAM hydrogel demonstrates a wide response temperature (24.1-33.2 °C), high light transmittance (Tlum = 87.5%), excellent solar modulation (ΔTsol = 71.2%), and robust mechanical properties. HBPEC is a functional material that can be used to adjust the lower critical solution temperature (LCST) of the smart window over a wide range by changing the degree of substitution (DS) of the butoxy group in its structure. In addition, the use of HBPEC effectively improves the light transmittance and mechanical properties of the hydrogels. After 100 heating and cooling cycles, the hydrogel still has excellent stability. Furthermore, indoor simulation experiments show that HBPEC/PNIPAM hydrogel smart windows have better indoor temperature regulation capabilities than traditional windows, making these smart windows potential candidates for energy-saving building materials.

Compost-diatomite-based phytostabilization course under extreme environmental conditions in terms of high pollutant contents and low temperatures

The effects of changes in environmental temperatures on the immobilization or removal of cationic potentially toxic elements (PTE) in heavily polluted soils are often poorly understood, although both are widely studied in the context of phytostabilization. To address this issue, a novel compost-diatomite hybrid (CDH) amendment was developed and applied for assisted phytostabilization at two external temperature regimes. (Cd/Ni/Cu/Zn)-extremely polluted soils (unenriched and CDH-enriched) were cultivated with perennial ryegrass and native soil microbiome under greenhouse conditions and then transferred to freeze-thaw conditions (FTC). The decrease in metal potential toxicity in soils subjected to phytostabilization following both temperature treatments was characterized by a combination of sequential extraction and atomic absorption measurements. The soil microbiome was characterized by high-throughput sequencing. In a relative comparison, the greatest decrease in the content of all PTEs in CDH-enriched soil (compared to unenriched soil) appeared in FTC. Furthermore, under the influence of FTC, in the relative comparison between two CDH-enriched soils (exposed-, and not-exposed- to FTC) and two unenriched soils (exposed-, and not-exposed- to FTC), the content of all PTEs decreased more sharply in the CDH-enriched series than in the unenriched series. The largest redistribution into four sequentially extracted fractions in CDH-enriched soil was found for Zn. Based on the distribution pattern, Zn immobilization was greater in CDH-enriched soil in FTC. CDH increased species richness in the soil, while FTC stimulated the growth of Bacteroidia, Alphaproteobacteria, Theromomicrobia, and Gammaproteobacteria. The analysis of the functionalities of the microbiome indicated enhanced metal transportation and defense systems in samples exposed to FTC. The current research is crucial for understanding how extreme environmental conditions in both cases high pollutant levels and low temperatures affect the movement and transformation of PTEs in polluted soils during phytostabilization.

FeverNet: Enabling accurate and robust remote fever screening

Remote human fever screening via thermal infrared imaging helps reduce the risk of respiratory disease transmission and plays an important role in public health monitoring. However, the accuracy of such systems often falls prey to variations in measurement distance and environment temperature. Most previous methods tend to employ sensors to overcome these variations, which are expensive schemes and have limited performance improvement. To address above problems, this paper presents a novel and robust remote fever screening framework named FeverNet. Specifically, FeverNet introduces depth estimation network and temperature distribution constraints across time periods to reduce the influence of distance variations and environment temperature changes. The fever attention module is thus proposed to enhance feature representation and expand the difference between fever faces and normal ones. In addition, we provide the Extended Thermal Infrared Face dataset (ETIF), which further gives visible images (paired with thermal infrared images) for depth estimation and improve the fever face generated method based on the maximum temperature of the face. Extensive experiments on ETIF demonstrate the advantages of our FeverNet over the state-of-the-art methods.

Spectral Characteristics of Water-Soluble Rhodamine Derivatives for Laser-Induced Fluorescence.

We present a comprehensive fluorescence characterization of seven water-soluble rhodamine derivatives for applications in laser-induced fluorescence (LIF)techniques. Absorption and emission spectra for these dyes are presented over the visible spectrum of wavelengths (400 to 700nm). Their fluorescence properties were also investigated as a function of temperature for LIF thermometry applications. Rhodamine 110 depicted the least fluorescence emission sensitivity to temperature at -0.11%/°C, while rhodamine B depicted the most with a -1.55%/°C. We found that the absorption spectra of these molecules are independent of temperature, supporting the notion that the temperature sensitivity of their emission only comes from changes in quantum yield with temperature. Conversely, these rhodamine fluorophores showed no change in emission intensities with pH variations and are, therefore, not suitable tracers for pH measurements. Similarly, fluorescent lifetime, which is also a property sensitive to local environmental changes in temperature, pH, and ion concentration, measurements were conducted for these fluorophores. It was found that rhodamine B and kiton red 620 have shorter fluorescence timescales compared to those of the other five rhodamine dyes, making them least suitable for applications where temporal changes in emission are monitored. Lastly, we conducted experiments to assess the physicochemical absorption characteristics of these dyes' molecules into polydimethylsiloxane (PDMS), the most common material for microfluidic devices. Rhodamine B showed the highest diffusion into PDMS substrates as compared to the other derivative dyes.

Autonomous Thermal Modulator Based on Gold Film‐Coated Liquid Crystal Elastsomer

AbstractRadiative cooling has been recently intensively explored for thermal management and enhancing energy efficiency. Yet, traditional materials with singular emissivity fall short in dynamic thermal management, highlighting the need for materials that can adjust their thermal radiation in real time. Active modulation methods, requiring external stimuli such as mechanical stretch, electric potential, or humidity change, offer adaptability but can increase energy use and complexity. Passive approaches, using materials' inherent thermal‐responsive properties, face manufacturing and scalability challenges. Here, a scalable yet effective passive approach is introduced for adaptive thermal modulation based on gold (Au) and liquid crystal elastomer (LCE) with a reversible response to environmental temperature changes. This modulator enables a “low thermal resistance” state through actuation‐induced microcracks that expose a high‐emissivity polymer substrate, and a “high thermal resistance” state by closing these microcracks and forming a high thermal resistance air gap between the modulator and the target object. The flexible design and fixed external dimensions of the Au‐LCE thermal modulator make it adaptable to various surface geometries. Furthermore, by adjusting the LCE's chemical composition, the modulator's transition temperature can be tailored, broadening its applications from enhancing building energy efficiency to improving clothing thermal comfort.

Change of Natural Oscillation Frequencies of Buildings and Structures Depending on External Factors

Abstract —This work is devoted to the development of the engineering seismic monitoring method created in Geophysical Survey of the Russian Academy of Sciences (GS RAS). In previous years, the “method of standing waves” was created and put into practice. It helps to separate natural oscillation modes of buildings and other engineering structures. The natural oscillations of hundreds of various objects (buildings, bridges, dams, etc.) had been studied and identified. We assumed that the physical condition of studied constructions could be controlled during exploitation by measuring the changes of natural oscillation frequencies. That would help to identify the appearance of defects in constructions, to prevent the risk of their destruction. However, it turned out that not everything is that simple: changes in frequency values are logically affected by changes in the environment around the studied objects. This article provides examples of these relations, influence of changes in environmental temperature, mass of objects and precipitation on the frequencies of natural oscillations.

Autonomous and heteronomous control of selectivity to pyrocatechol derivatives for near-infrared light-responsive cup-stacked carbon nanofiber/FTO electrodes modified with thermo-responsive polymers

Autonomous and heteronomous switchable selectivity for electrochemical reactions was examined in an electrolyte solution containing pyrocatechol (PC) and dopamine (DA) using a fabricated thermo- and photo-responsive poly(N-isopropylacrylamide) (PNIPA)-modified cup-stacked carbon nanofiber (CSCNF) electrode. PNIPA can be autonomously and reversibly switched by environmental temperature changes between hydrophilic expanded coil structure and hydrophobic collapsed globule structure. CSCNFs as the electrode materials can effectively convert absorbed external near-infrared (NIR) light into heat. Although the molecular size of DA is larger and the octanol-water partition coefficient of DA is smaller than those of PC, both PC and DA could permeate to the CSCNF electrode surface through the expanded coil structure of the PNIPA layer at 25 ˚C, which temperature is below the lower critical solution temperature (LCST), causing their electrochemical signal readout. In contrast, transport of DA to the electrode surface was selectively suppressed by exposing the polymer to temperature at 45 ˚C, which value is above the LCST, or NIR light irradiation (> 940 nm, ca. 77 mW cm–2) to the CSCNF electrode surface even at 25 ˚C due to the steric hindrance and hydrophobicity of collapsed globule structure of the polymer layer. This resulted in the preferential electrochemical signal of PC. The switchable sensitivity of the electrode also allowed it to be successfully demonstrated for the simultaneous determination of PC and DA even at a single transducer, though electrode arrays with different sensitivity and selectivity are widely used for the determination of multiple chemicals simultaneously.

Effect of long-term temperature-controlled rearing on growth traits and sexual maturity of common carp (Cyprinus carpio)

Many economically important fish have a long sexual maturation cycle, with the first sexual maturation time exceeding four years, which poses a long-term challenge for the cultivation of excellent varieties of these fish. Gonadal development and reproductive timing of fish are closely related to changes in environmental temperature. This study used the common carp as an economic fish model and set up three aquaculture modes for a one-month old common carp population: constant temperature test group (CTTG), normal temperature control group (NTCG), and variable temperature control group (VTCG). A long-term (approximately 11 months), temperature-controlled aquaculture experiment was conducted. The results of growth traits and gonadal development tests showed that at 10 months, the body length and weight of the CTTG were significantly higher than those of the other two groups. At seven months, the gonadosomatic index (GSI) value of CTTG was also significantly higher than that of the other two groups; At 10 months, the serum estradiol (E2) concentration of CTTG was significantly higher than that of the other two groups, while the testosterone (T) levels of VTCG and CTTG were significantly higher than those of NTCG, and only the 11-ketotestosterone (11-KT) concentration of VTCG was significantly higher than that of the other two groups. Simultaneously, qPCR analysis of sex hormone regulatory genes revealed that the expression of Cyp19a1a in CTTG ovaries was significantly higher than that in NTCG and VTCG ovaries, whereas the expression of Cyp11b and Hsd11b2 in VTCG ovaries was significantly higher than that in NTCG and CTTG ovaries. At 12 months, artificial reproduction revealed that only fish from the CTTG (66.67%) successfully laid eggs and fertilized normally. The results indicate that long-term constant temperature cultivation at 28 °C starting from the juvenile stage is not only beneficial for the body growth of common carp, but also promotes their gonadal development. This may be due to the conversion of T into E2 by Cyp19a1a in the common carp, ultimately facilitating the functional development of gonadal tissue under hypothalamus-pituitary-gonadal (HPG) axis regulation, normal egg laying, and fertilization. This study reduced the normal first sexual maturation time of common carp by at least 50% and provides a reference for the rapid cultivation of excellent varieties of other economically important fishes.

Analysis and visualization of spatio-temporal variations of ecological vulnerability in Pakistan using satellite observation datasets

Pakistan is the fifth most populous country in the world. Its ecological environment is facing numerous stresses such as climate change, rapid urbanization, natural disasters, and a decline in air quality. Thus, the scientific understanding of spatial and temporal changes in Pakistan's ecological environment is crucial for formulating an informed strategy for regional sustainability. This study used the Google Earth Engine platform and the Remote Sensing Ecological Index (RSEI) to investigate ecological vulnerability in three provinces of Pakistan for 1990, 2000, 2010, and 2020. Landsat 5 and Landsat 8 datasets are used to construct RSEI indicators and Principal Component Analysis (PCA) is adopted to objectively compute RSEI for the past three decades. The results indicated that (1) the ecological vulnerability of the Punjab province exhibited a slightly improved trend from 1990 to 2020 with overall dominance of ‘moderate’ level vulnerability in all four years; (2) The Sindh province has exhibited a declining trend of the ecological environment with ‘poor’ ecological vulnerability contributing to 28.6% of the total area in 2020 as compared to 1.04% of the total area in 1990; and (3) The ecological environment of Balochistan province has shown resilience to some extent during 1900–2010 with the dominance of a ‘moderate’ level of ecological vulnerability. However, a decline is observed between 2010 and 2020. These research results can provide support for the Punjab, Sindh, and Balochistan provinces in achieving sustainable development while conserving the regional ecological environment.

Simultaneous measurement of temperature and humidity using a dual-parameter sensor based on SPR and no-core fiber technology

In this article, we present a surface plasmon resonance (SPR) sensor based on a no-core fiber (NCF) structure for simultaneous measurement of temperature and humidity. The sensor is simulated by depositing a silver film on the exterior of the NCF by magnetron sputtering, followed by the application of a composite thin film of polyvinyl alcohol (PVA) and polydimethylsiloxane (PDMS). This configuration induces SPR resonance phenomena at two distinct wavelengths, resulting in the splitting of the resonance peak into two distinct peaks, enabling simultaneous measurement of temperature and humidity. To achieve optimal sensor performance, the thickness of the PDMS-PVA composite film, the proportion of sensitive materials, the thickness of the silver film, and the structural parameters of the fiber were optimized. Simulation results show that the sensor exhibits a humidity sensitivity of 8.60 nm/%RH over a relative humidity (RH) range of 50%–100%. The highest temperature detection sensitivity achieved is 7.40 nm °C−1. This sensor holds great potential for applications in monitoring changes in environmental temperature and humidity.