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排序方式: 共有331条查询结果,搜索用时 15 毫秒
71.
Asad Nawaz Shinawar Waseem Ali Sana Irshad Fatima Irshad Aftab Ahmed Zainab Sharmeen Imran Khan 《International Journal of Food Science & Technology》2020,55(6):2344-2351
The current study investigates the comparison and quality characteristics of starches isolated from potatoes using different processing methods from three commercial varieties: Lady Rosetta, Asterix and Challenger, for the first time in Pakistan. The analysis of variance revealed that starch yield significantly (P < 0.05) depended on total solids, peeling (12.7%, 12.0% and 12.0%) and unpeeling (15.0%, 14.0% and 14.0%) of potatoes compared to potato varieties for Lady Rosetta, Challenger and Asterix, respectively. Moreover, pasting properties, protein content, redness and yellowness were increased in those starches isolated without peeling while carbohydrates and lightness were increased in peeled potato starches. Furthermore, Fourier-transform infrared spectroscopy analysis revealed that protein (1200–1400 cm−1) was present in starch extracted without peeling. Besides, scanning electron microscopy analysis revealed oval-shaped starch granules with no impurities in peeled potato starch. The findings suggest the suitability of peeling process for obtaining a high-quality pure starch. 相似文献
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73.
The Internet of Things (IoTs) is apace growing, billions of IoT devices are connected to the Internet which communicate and exchange data among each other. Applications of IoT can be found in many fields of engineering and sciences such as healthcare, traffic, agriculture, oil and gas industries, and logistics. In logistics, the products which are to be transported may be sensitive and perishable, and require controlled environment. Most of the commercially available logistic containers are not integrated with IoT devices to provide controlled environment parameters inside the container and to transmit data to a remote server. This necessitates the need for designing and fabricating IoT based smart containers. Due to constrained nature of IoT devices, these are prone to different cyber security attacks such as Denial of Service (DoS), Man in Middle (MITM) and Replay. Therefore, designing efficient cyber security framework are required for smart container. The Datagram Transport Layer Security (DTLS) Protocol has emerged as the de facto standard for securing communication in IoT devices. However, it is unable to minimize cyber security attacks such as Denial of Service and Distributed Denial of Service (DDoS) during the handshake process. The main contribution of this paper is to design a cyber secure framework by implementing novel hybrid DTLS protocol in smart container which can efficiently minimize the effects of cyber attacks during handshake process. The performance of our proposed framework is evaluated in terms of energy efficiency, handshake time, throughput and packet delivery ratio. Moreover, the proposed framework is tested in IoT based smart containers. The proposed framework decreases handshake time more than 9% and saves 11% of energy efficiency for transmission in compare of the standard DTLS, while increases packet delivery ratio and throughput by 83% and 87% respectively. 相似文献
74.
Azeem Irshad Muhammad Sher Omer Nawaz Shehzad Ashraf Chaudhry Imran Khan Saru Kumari 《Multimedia Tools and Applications》2017,76(15):16463-16489
The security for Telecare Medicine Information Systems (TMIS) has been crucial for reliable dispensing of the medical services to patients at distant locations. Security and privacy element needs to be there for any physician or caregiver to make certain an appropriate diagnosis, medical treatment or any other exchange of critical information. In this connection, many relevant TMIS-based authentication schemes have been presented, however various forms of attacks and inefficiencies render these schemes inapplicable for a practical scenario. Lately, Amin et al. proposed a scheme based on a multi-server authentication for TMIS. However, the Amin et al., scheme has been found vulnerable to user and server impersonation attacks. We have proposed an improved model with higher performance and efficiency, as evident from the forthcoming sections. Besides, the scheme has been backed up by formal security analysis using BAN logic to ensure the resilience of the proposed scheme. 相似文献
75.
76.
77.
Wireless Personal Communications - The small cell technology is considered as a key technology for 5G networks. The capacity expansion and coverage extension are both achieved through this... 相似文献
78.
Abdul Saboor Ahmad Nawaz Khan Rahim Jan Saqib Sharif Munawar Khan 《Journal of Polymer Research》2018,25(12):248
The malfunction of electronic devices and many health-related issues may be caused due to electromagnetic interference (EMI) pollution. To overcome this problem a new set of material SAN/PANI/FLG hybrid composite with better EMI shielding properties is prepared using solution casting technique. Conductive polyaniline (PANI) is added (5 wt% and 10 wt%) to otherwise, an insulative polymer styrene acrylonitrile (SAN). Furthermore, few layer graphene (FLG) is added (0.1–1 wt%) to SAN/PANI polymer blends for preparation of SAN/PANI/FLG hybrid composites. The incorporation of PANI in SAN produces a phase separated morphology, whereas graphene appears in sheet like structure. For 0.1 wt% FLG/SAN/PANI-10 composite, total shielding effectiveness (SET) is enhanced from 1.1 to 24.3 dB (100 Hz), mainly due to enhanced dielectric characteristics. However, the maximum increase in tensile strength (49.6 MPa) and modulus (1.5 GPa) is observed for 0.5 wt% FLG/SAN/PANI-5.0 hybrid composite. The increase in dielectric properties and shielding efficiency of SAN/PANI/FLG may be credited to the accumulation of space charges or electric dipoles at the insulator conductor-interface. 相似文献
79.
Influence of different land-cover types on the changes of selected soil properties in the mountain region of Rawalakot Azad Jammu and Kashmir 总被引:1,自引:0,他引:1
M. Kaleem Abbasi Mohsan Zafar Sumyya Razaq Khan 《Nutrient Cycling in Agroecosystems》2007,78(1):97-110
The study focused on the impact of change in land-cover types on soil quality inferred by measuring the relative changes in
chemical and physical properties of non-disturbed and disturbed soil system. Soil samples were collected from major land-cover
types in the mountain region: natural forest, grassland and cultivated land (arable). The natural forest served as a control
against which to assess changes in soil properties resulting from the removal of natural vegetation or cultivation of soil.
Soil samples were collected from 0–15 and 15–30 cm depth six times during the year and examined for their nutrient status,
i.e. soil organic matter (SOM); total N (TN); available P (AP); available K (AK); cation exchange capacity (CEC), pH and physical
properties like particle size distribution, bulk density (BD), and porosity. Significant differences among land-cover types
were found for SOM, TN, AP; AK, CEC and pH. Soil collected from the forest had the highest levels of all nutrients followed
by grassland while soil from the arable site had very low nutrient status indicated an extractive effect of cultivation and
agricultural practices on soil. With significantly lower clay contents (20%), texturally the soil of arable site was quite
different from that of the natural forest and grassland. Similarly, a 13% more BD and 12% lower porosity showed structural
deterioration of arable soil. The changes in clay contents, BD and porosity due to cultivation suggest adverse effects on
environmental protection functions of soil. The correlation coefficient between OM to TN, AP, AK and CEC suggesting that within
a narrow range of soil, OM may serves as a suitable indicator of soil quality. Natural vegetation appeared to be a main contributor
of soil quality as it maintained the organic carbon stock and increased the nutrient status of soil and is therefore, important
to sustain high-altitude ecosystems and reinstate the degraded lands in the mountain region. 相似文献
80.
Iram Shaheen Haq Nawaz Bhatti Tallat Ashraf 《International Journal of Food Science & Technology》2008,43(7):1152-1158
Production of invertase employing a newly isolated Fusarium sp. under solid-state fermentation was optimised. Different process parameters were optimised. The maximum enzyme activity under optimum conditions was 47.23 ± 2.12 U gds−1 with nitrogen additives. The enzyme was purified by ammonium sulphate precipitation, diethylaminoethyl cellulose ion-exchange chromatography and Sephadex gel filtration. This protocol gave 20.25-fold purification and 5.53% recovery. The optimum pH and temperature for activity were 5.0 and 50 °C. The K m and V max values for the enzyme were 8.33 m m and 21.48 μmol min−1 , respectively. A detailed kinetic study of thermal inactivation has been carried out. Enthalpy of activation (Δ H *) decreased when entropy (Δ S *) of activation increased at higher temperatures. Moreover, free energy of denaturation (Δ G *) increased at higher temperature making the enzyme thermally stable. A possible explanation for the thermal inactivation of invertase at higher temperatures is also discussed. 相似文献